Topics: The notion of Categorical Abstract Machine (CAM). Evaluation in a Cartesian closed category (c.c.c.). Evaluating map. Environment. Examples of expression evaluation. Collision of variables. Eliminating the collision. De Bruijn's encoding. De Bruijn's numerals. Evaluation in a c.c.c. using De Bruijn's encoding. Combinatory glue. The properties of the theories of computation.